The mailbox import tool allows you to transfer your mail from another server to your domain. You need to specify the login and password for the mailbox and wait until all letters are transferred while preserving the structure, including nested folders.
Mailbox import is available in the tab - Mail - Mail import.
If necessary, you can specify the host of the remote server, port and connection type in the advanced settings.
Depending on the volume of the mailbox contents, the transfer will take some time.
Please note that the transfer does not include setting up the rules for sorting letters. If you have set up rules for sorting letters on your current mail, you will need to create them again in the mail web interface at http://webmail.domain.tld/, where domain.tld is the name of your domain after the migration is complete.